Encased electric pump



Nov. 25, 1969 J. J. CARDOSO 3,479,960

ENCASED ELECTRIC PUMP Filed Dec. 26, 1967 8 Sheets-Sheet 1 FIG. 1.

usrmzvk JOSE JOAQUIM CARDOSO ATTOEI Y Nov. 25, 1969 J. J. CARDOSO 3,479,960

ENCASED ELECTRIC PUMP Filed Dec. 26, 1967 s Sheets-Sheet 2 FIG. 2.

INVENTOB JOSE JOAQU IM SO BY f I v I New 5, 1969 J. J. CARDOSO 3,479,960

ENCASED ELECTRIC PUMP Filed Dec. 26, 196' 8 Sheets-Sheet 5 INVENTOE JOSE. JOAQUIM CARDOSO by M4 ATTPJI/Z'Y Nov'. 25, 1969 J. .1. CARDOSO 3,479,960

ENCASED ELECTRIC"PUMP Filed Dec. 26, 1967 8 Sheets-Sheet 4 INVENTOE JO6E JOAQUIM CARDOSO BY Mi. W

Nov. 25, 1969 J. J. CAR'DOSO ENCASBD ELECTRIC PUMP 8 Sheets-Sheet 5 Filed Dec. 26, 1967 JNVENTOR JOSE JOAQUIM CARDOSG ATTOJQ-A/Ey Nov. 25, 1969 J. J. cARDosO ENCASED ELECTRIC PUMP 8 Sheets-Sheet 6 Filed Dec. 26, 1967 Nov. 25, 1969 J. J. CARDOSO ENCASED ELECTRIC'PUMP 8 Sheets-Sheet 7 Filed Dec. 26, 1967 Fla. 9.

INVENTQE 2O JOSE JOAQUIM CAR'DO5O United States Patent 3,479,960 ENCASED ELECTRIC PUMP Jose Joaquim Cardoso, Belo Horizonte, Brazil, assignor to Magnesita S.A., Minas Gerais, Brazil, a corporation of Brazil Filed Dec. 26, 1967, Ser. No. 693,232

Claims priority, application Brazil, Dec. 26, 1966,

186,674; Sept. 20, 1967, 193,486

Int. Cl. F04c 1/06, 15/00 US. Cl. 103-117 3 Claims ABSTRACT OF THE DISCLOSURE An electric motor driven gear pump wherein a resilient, helically shaped hollow member is rigidly secured in a tubular shaft which is rotatably driven by the rotor of the motor. A helical gear member is disposed within said hollow member and is fixed at opposed ends to the pump housing so that it remains stationary while the resilient hollow member rotates around it to axially move fluid through the hollow member and said tubular shaft.

This invention relates to electric motor driven gear pumps and is particularly directed to an electric pump embodying generally the principles disclosed in US. Patents No. 1,892,217 and No. 2,028,407 which are commonly known as and will hereinafter be referred to as Moineau type pumps.

Basically the principle of a Moineau pump, which has enjoyed worldwide use and recognition, is one of hypocycloidal action. The rotor of this type of pump is made of stainless steel, whereas the stator is made of a resilient material, preferably an elastomeric product known under the trade name Hypalon, manufacture by E. I. du Pont de Nemours. Both the rotor and stator are of helical form. In this type of pump the flow of liquid or fluid to be pumped provides a positive displacement effect with the pumped liquid or fluid being literally squeezed forwardly by the revolving action of the rotor. Since this revolving action is continuous without loss of movement the displacement of the cross sectional area occupied by the liquid or fluid is constant and therefore flows uniformly.

The primary object of the present invention is to embody the basic principles of the Moineau type pump in an electric motor.

This object is accomplished by providing a hollow drive shaft in an electric motor to serve as a carrier for a rotor which is made of elastomeric material and surrounds a fixedly mounted stator which is made, for example, of stainless steel. The configuration of the rotor and the stator are identical to the helical configuration of their counterparts in the Moineau pump but reversed as to their normal action relative to each other.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the invention consists in the novel construction combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

Referring to the drawings:

FIGURE 1 is a side elevation partly in section, of an electric motor driven gear pump embodying the invention which is adapted to be mounted in a horizontal operating position.

FIGURE 2 is a side elevation similar to FIGURE 1 but illustrating the pump in a vertically mounted operating position.

FIGURE 3 is an enlarged elevation of the gear, pump body and drive shaft according to the present invention.

FIGURES 440 show diagrammatically the progressive action of a helicoidal rotor of a Moineau type pump as it axially moves the fluid contained between the rotor and stator.

FIGURES 5 and 6 are diagrammatic illustrations of the hypocycloidal action involved in the working principle of a Moineau type pump.

FIGURE 7 is a perspective view of a vertically mounted pump according to the present invention, the details of which are shown in FIGURE 2.

FIGURE 8 is a perspective view, partly in section, of a horizontally mounted pump according to the present invention, the details of which are shown in FIGURE 3.

FIGURE 9 is a side elevation, partly in section, of a submersible pump according to the present invention.

FIGURE 10 is graph showing recommended pumps for various combinations of heights and capacities.

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

Reference will first be made to the working principle of a Moineau pump which is based on a hypocycloidal action, as shown in FIGURE 5 of the attached drawings, and exemplified in FIGURE 6.

There is shown in FIGURE 6 an iron tool comprising a plate of generally elliptical shape and secured to an iron stem as shown in (a). Assuming that the stator of the Moineau pump is made of ice and is cylindrically shaped as indicated in (b), and assuming further that the tool (a) is heated, when the tool is pressed against the block of ice with a slow rotational movement, it will form a helix shaped opening in the block of ice, as shown in (c) of FIGURE 6.

Considering the same heated tool reduced to a single circular cooled washer secured to a shaft having an eccentric knee, as in (d) of FIGURE 6, said disc will then follow an eccentric rotation and it will be passed through the open stator helix from one end to the other, exactly as occurred in the generation of said helical shape. Then, if the rotor is made as a solid body in following the path of said disc (d), i.e., if the rotor is displaced adjustably inside the helix in the stator, a vacuum will initially be produced in between the alternate helix spacings.

On a cycle of revolution, the true rotor center will describe a complete orbit in a direction opposed to the rotation of the rotor. Thus, in a revolution of the control shaft, the liquid at the helix entrance is forced to occupy the hollow part of the stator in the same direction. The fluid speed in relation to the element in movement is uniformly differential, although comparatively lower than in other type pumps. This permits, with low rotations, obtaining with this type of pump the same performance obtained with the well known centrifugal pump for the same characteristics, but running at twice the speed.

Up to this point, reference has been made only and exclusively to the Moineau pump, and such pump will continue to be referred to in order to explain its superiority.

The turbine pump, as is the case with the centrifugal pump, uses the whirling effect of the water which causes the flowing of the fluid and the resultant pressure buildup. Piston, gear and screw pumps push the water and the pressure is directly applied to the same. In the Moineau pump the flow of the liquid or fluid to be pumped can be considered as resulting from the displacement of a piston inside a cylinder having infinite length. The dis: placement effect is therefore positive. In its action, the rotor rotates inwardly of the stator surface, and thus the pumped liquid is literally squeezed forwardly by the revolving action with a minimum of turbulence. As the revolving action of the rotor inside the stator is continuous without loss of movement, the displacement of the cross sectional plane occupied by the liquid is constant, and therefore the same flows uniformly. In brief, the Moineau pump is the only pump which uses the positive displacement of a constant pumping action, which literally squeezes the water or fluid forwardly as mentioned above.

Referring now to the present invention and particularly to FIGURES 1 and 2 of the drawings, there is shown the Moincau type pump principle adapted to the present invention, wherein the pump proper comprises a stationary worm shaft or involute gear 1, and a rotatable pump body 2. The gear 1 is preferably made of stainless steel and has two steel connecting cables 1a, 1b covered with a resilient material extending from each of its threaded ends. Said cables are connected to the gear 1 by means of stainless steel threaded sleeves and have clevis type connecting means 10, 1d at their outer ends to permit their attachment to plates 8' secured in the end covers 8 of the central motor housing 7. Thus, gear 1 is stationary and is prevented from axial rotation but is subject to a small orbital displacement inside the pump body 2 since the cables 1a, 1b being somewhat flexible, are subject to some torsional force when the pump is in operation. The orbital displacement of the gear is of advantage when the fluids being pumped contain solid particles in that it facilitates their passage through the outlet end of the pump.

The pump body 2 is made of a resilient elastomeric material and is rigidly secured in a steel tube 3 which replaces the usual driven shaft of the motor. The body 2 is secured in tube 3 by appropriate means such as set screws 16 (FIGURE 3) and includes washers 3' about the ends of the body 2 to prevent axial displacement thereof relative to the tube 3. At the ends of the tube 3 are provided high pressure sealing gaskets as ordinarily used in centrifugal pumps. The flanged end members 12 and 13 are secured to the end covers 8 of central housing 7 for appropriate connection to inlet and outlet means not shown.

The motor proper is an ordinary, asynchronous, induction type motor, whose axle or drive shaft comprises the steel tube 3 in which the pump body 2 is secured, as previously described. The tube 3 is rigidly secured to the motor rotor 4 for rotation therewith and is journalled at each end on bearings 9 for either horizontal or vertical mounting, as seen in FIGURES 1 and 2, respectively. In FIGURE 1 ball bearings are shown, whereas roller bearings are shown in FIGURE 2. The motor includes a stator 5 which has the usual winding 6 made of magnetic wire which is supported on the central motor housing 7. The two housing covers 8 support the bearings 9, the sealing gaskets 10, and the flanged end coupling members 12 and 13, respectively, for the inlet and outlet of the fluid being pumped.

In FIGURES l and 8, the assembly is adapted to be mounted horizontally, and for this purpose a foot 11, integral with central motor housing 7 is provided. In FIGURES 2 and 7 the assembly is adapted for vertical mounting and the lower cover 8 is provided with an integral foot 11'. The electric terminals of the motor stator winding are contained inside a terminal box 14.

FIGURE 9 shows a submersible electro-pump identical to the pumps shown in FIGURES 1 and 2 so far as its main parts are concerned, but modified as necessary in view of its intended use. The electric motor which has the same essential parts such as the stator 5, winding coils 6, rotor 4, ball bearing means 9, and the rotor tube 3, is a specially built motor, usually of comparatively small size to permit it to be easily disposed inside Wells or 4 holes of small diameter. The pump proper, comprising pump body 2 and its gear 1, can in this case be of greater length to permit greater forcing pressure, but has a smaller diameter than the pumps of FIGURES 1 and 2 which limits its capacity.

The gear 1 is secured against rotation to the lower housing cover 20 in a manner similar to the securing means of FIGURES 1 and 2, by a flexible support such as a steel cable 21 and a mounting pin 22. The upper support or cable used in the construction of FIGURES l and 2 is dispensed with and the upper end of gear 1 extends beyond upper washer 3'. Lateral support for the gear is of course provided by surface contact of the gear with the pump body. As is the case with the construction of FIGURES 1 and 2, there is a small orbital displacement of gear 1. The lower cover 20 has a peripheral portion of wire mesh or a perforate metallic plate 17 through which the liquid being pumped passes. The upper motor housing cover 23 includes in addition to the sealing gasket arrangement 10, a fluid-tight terminal box 18 through which the electric cable 19 carrying the electric motor feed leads extends. Said sealing gaskets 10 can be of conventional cord type or of a retention-compensating nature, as desired.

The liquid to be pumped will be forced upwardly under pressure of the hypocycloidal action of the pump to an outlet pipe 26 connected by a sleeve 24. The housing end covers are bolted to a central motor housing 7 by a sufficient number of bolts 25. Sealing members 15 made of resilient material such as natural rubber are disposed between the housing members to assure the required fluidtightness of the electric motor in relation to the liquid or fluid being pumped.

I claim:

1. An electric motor driven pump comprising in combination a casing including an inlet end and an outlet end, a stator and a rotor within said casing, a hollow shaft secured to said rotor for rotation therewith and communicating with the inlet and outlet ends of said casing, a resilient hollow pump body provided with a helical inner surface and rigidly secured within said hollow shaft, a helical gear member within said hollow pump body and in surface contact with the helical inner surface thereof, means securing said gear member to said casing against rotation, said means comprising flexible members secured to each end of said gear member, plate members carried by said casing, the free ends of said flexible members connected to said plate members, whereby said gear member is subject to a slight orbital movement when said pump is in operation, and rotation of said pump body around said gear member forces fluid to be pumped by hypocycloidal action from the inlet end of said casing through the outlet end thereof.

2. An electric motor driven pump comprising in combination a casing including an inlet end and an outlet end, a central body portion, cover members connected to opposite ends of said body portion in fluid-tight relation ship thereto, the cover member at the inlet end of said casing including a solid bottom wall and a perforate side wall, a stator and a rotor within said casing, a hollow shaft secured to said rotor for rotation therewith and communicating with the inlet and outlet ends of said casing, anti-friction bearing members in each of said covers for supporting said hollow shaft, a resilient hollow pump body provided with a helical inner surface and rigidly secured within said hollow shaft, a helical gear member within said hollow pump body and in surface contact with the helical inner surface thereof, means securing said gear member to said casing against rotation, whereby rotation of said pump body around said gear member forces fluid to be pumped by hypocycloidal action from the inlet end of said casing through the outlet end thereof.

3. A pump according to claim 2 wherein said helical gear member is of greater length than said pump body and the means securing said gear member to said casing 5 6 comprises a flexible member, one end of which is se- 2,290,137 7/1942 Aldridge. cured to an end of said gear member and the other end 2,409,688 10/1946 Moineau 103-121 of which is secured to the cover member at the inlet end of said casing. DONLEY J. STOCKING, Primary Examiner References Cited 5 W. I. GOODLIN, Assistant Examiner UNITED STATES PATENTS 1,759,766 5/1930 Szmukler 103 11s 2,028,407 1/1936 Moineau. 

